Aleris International, for example, is developing an
aluminium-magnesium-scandium alloy that it says is 5 percent
lighter than conventional aircraft aluminium and could be ready
for later production of next-generation Airbus A320neo
and Boeing 737MAX jets.

Nearly 90 percent of the 9,600 aircraft on order with Boeing
and Airbus are metallic, said Ingrid Jorg, senior vice president
of Aleris, mainly because smaller jets won't use composite
fuselages for decades, if ever.

"If you don't expect single-aisle planes to turn to
composites before 2030, then there's a lot of demand," she said.

The advent of composites with the Boeing 787 a decade ago
looked likely to undercut the aerospace aluminium industry. But
years of research into lighter, more useable alloys is coming to
fruition. Their use could keep aluminium demand strong for
years, particularly in Asia.

The new materials face tests in labs and regulatory
approval. They are also are more expensive than conventional
aluminium. But aluminium's long use in aerospace means many
properties are well known. And some new alloys can compensate
for high cost with better manufacturing use.

The Aleris aluminium-magnesium alloy can be welded, for
example, replacing millions of fasteners on Airbus and Boeing
jets, says Jorg. Some aluminium-lithium alloys can cut weight by
8 percent over traditional alloys.

LARGER PLANE CHALLENGE

Still, composites are a key feature of next-generation large
planes that are the centre of attention at the Paris Airshow.
The Airbus A350's maiden flight last week provided another
showcase for composites.

Plastic composites account for half of the weight of
Boeing's 787 Dreamliner and Airbus' A350, eroding aluminium's
traditional dominance in materials for those planes.

This tussle in plane materials mirrors growing competition
in car making between dominant material steel and aluminium,
which is the lighter challenger in this market.

Aluminium makers accept composites are firmly established in
wide-body aircraft, but say that after a first rush of composite
demand, jet makers are being more pragmatic about materials so
they can fulfil hefty orders and avoid further programme delays.

"We believe that the aircraft of tomorrow will be hybrid -
there will be no full aluminium aircraft and no full composites
aircraft," Christophe Villemin, head of aerospace and transport
at aluminium products group Constellium, said.

Boeing's plans to use an aluminium fuselage on a future
redesign of its 777 jet, rather than a composite design as used
on the fast-selling but heavily delayed 787, has brought welcome
news for aluminium makers. Boeing said it is considering an
aluminum-lithium alloy for the jet.

The market for these mid-sized, twin-aisle jets is estimated
by Boeing as worth $1 trillion over the next 20 years.

Aluminium firms like Alcoa Inc say their latest
alloys are in line with composites in low density, and that they
can make healthy margins even when losing volume share.

"The 787 generates for Alcoa over 80 percent higher value
per shipset than the all-metal 767 that it is replacing, and
three-times the ship-set value of a 737," said Olivier Jarrault,
head of Alcoa Engineered Products & Solutions Group.

YEARS OF METAL AHEAD

Aluminium alloys have not been without teething problems.
Cracks in the wings of Airbus' A380 super-jumbo have been linked
to alloy brackets used to join aluminium and composite parts.

Such joining issues are a big area of development, with
metal and plastics set to co-exist for some years, and Alcoa
says its fasteners business already made up almost 30 percent of
its $3.8 billion in aerospace sales last year.

In the segment of smaller, single-aisle planes, aluminium
makers expect the metal's continued dominance and are talking up
their experience in this high-volume market.

Because single-aisle planes can use thinner aluminium skins,
composites don't provide as much weight benefit, said Matthias
Miermeister, manager of field engineering at Aleris, which
recently opened a $350 million aluminium factory in China to
meet demand.

Overall expansion in plane manufacturing is expected to
yield another record number of plane deliveries this year, and a
long order backlog should sustain a similar pace for the rest of
the decade, providing enough demand for metal and composites.

Composite suppliers boast the more spectacular growth as
planemakers step up deliveries of new models. Hexcel Corp
says it averaged 12 percent annual growth in commercial
aerospace sales over 2004 through 2012.

Yet global aluminium use in aerospace should grow about 2.4
percent a year between 2010 and 2020, and on average, the metal
still makes up 70 percent of aircraft structural weight, Metal
Bulletin Research analysts estimate.

"I don't see a real threat for aluminium in aeronautics in
the 10 years ahead," Antoine Chacun, managing director of French
brokerage Oddo Metals, said. "All our rolling mill clients seem
to be at full capacity and looking to add more."